1. Field of the Invention
The present invention pertains to a sludge extractor with a receiving tank, on which are mounted a suction connection for a suction element, which draws in a sludge-containing liquid, and a discharge connection for a discharge element, which discharges the sludge-containing liquid, the extractor also being equipped with a motor to drive a suction device in such a way that a negative pressure, which keeps a vacuum valve on the discharge element closed, is created in the receiving tank.
2. Description of the Prior Art
A sludge extractor of this type is known from DE 199 42 187 A1. The suction process is begun by turning on the motor. The receiving tank fills up slowly with sludge-containing liquid until the liquid reaches the level of the vacuum valve. The vacuum valve is closed because of the prevailing negative pressure. When a the liquid reaches a certain limit in the receiving tank, a ball valve closes, as a result of which the motor begins to run audibly faster. This is a sign to the user that it's time to turn off the motor. Turning off the motor has the effect of eliminating the negative pressure in the receiving tank. The internal pressure now being produced by the sludge-containing liquid has the effect of opening the vacuum valve, and the sludge-containing liquid can now escape through the discharge element until the receiving tank is empty again. Then the user can turn the motor on again to repeat the process as often as necessary.
A sludge extractor of this type therefore suffers from the disadvantage that the receiving tank, which fills up relatively quickly, can only be emptied discontinuously, by turning off the motor.
A procedure of this type leads to many interruptions in the suction process itself, and many users find this annoying.